Re: [XEN PATCH v1] libxl: use getrandom() syscall for random data extraction

[Julien Grall <julien@xxxxxxx>]

Hi,

On 24/05/2021 09:58, Sergiy Kibrik wrote:
> Simplify libxl__random_bytes() routine by using a newer dedicated syscall.
> This allows not only to substantially reduce its footprint, but syscall also
> considered to be safer and generally better solution:
>
> https://lwn.net/Articles/606141/
>
> getrandom() available on Linux, FreeBSD and NetBSD.
From the man:

VERSIONS
       getrandom() was introduced in version 3.17 of the Linux kernel. 
 Support was added to glibc in version 2.25.
If I am not mistaken glibc 2.25 was released in 2017. Also, the call was 
only introduced in FreeBSD 12.
So I think we want to check if getrandom() can be used. We may also want 
to consider to fallback to read /dev/urandom if the call return ENOSYS.
Cheers,

--
Julien Grall